I see in the email archives that this feature is controversial. From
the discussion I understand the following:
[summary]

That's an excellent summary.

Thus my question is: does PLT Scheme have syntax location features
that this SRFI proposal is not able to provide?

There is one that it would in principle be able to provide but chooses not to:
The SRFI proposal requires the first argument of datum->syntax-object to be an
identifier, as indeed Chez does, while PLT allows an arbitrary syntax object
there.

There is no fundamental reason why this cannot be supported, but it
would make the reference implementation more complex. Also,
I don't know how useful this feature really is in practice.